Not Applicable.
Not Applicable.
This invention relates generally to hopper tees and, more specifically, to a low-profile, swing-away hopper tee and valve assembly.
Hoppers or tank trailers commonly are used to transport bulk commodities such as industrial and food products. When the hopper or tank trailer reaches its destination, the bulk commodity is unloaded. Typically this is done by pneumatically unloading the bulk commodity from the hopper into a clean and sanitary pipe line. For this purpose, hopper tees are mounted to the discharge outlet of the hopper truck. The hopper tee conventionally has a vertical section and a horizontal section forming the tee configuration. To transfer the bulk commodity, the material is moved out of the hopper by gravity flow or air pressure vibration into the vertical section of the hopper tee. The clean pipe discharge pipe is connected to the horizontal section of the tee. Pneumatic conveyance of the material through the pipe is accomplished by establishing a pressure differential in the pipe.
Prior art hopper tees have been constructed by welding vertical and horizontal pipe sections together. Such tees are prone to excessive wear and failure. I addressed such problems in my prior U.S. Pat. No. 4,848,396 which discloses a cast hopper tee designed to provide a smooth and uninterrupted internal transitional surface; and in my prior U.S. Pat. No. 5,387,015 which provides for a hopper tee having an elliptical opening and a pair of wear saddles creating double wall thicknesses at the transition areas between the vertical and horizontal pipes.
Although my prior hopper tees function well for their intended purposes, there are several problems associated with the prior hopper tees. The prior hopper tees are formed as a complete, one piece unit having a vertical section and a horizontal section. The hopper tees are designed to fit on the bottom of pneumatic tank trailers. The valve and the hopper tee are bolted to a flange. To remove the hopper tee the bottom line piping and the valve must be removed. The user must use wrenches to unbolt 4, 6 or 8 bolts that hold the hopper tee, the valve and the line to the bottom of the hopper. An excessive amount of time is used to perform such a task.
Further, when the user is washing the trailer and changing product, for example, from a load of black plastic pellets to white plastic pellets, just one black plastic pellet can contaminate a complete bin of white plastic pellets. Likewise, one kind of residual polymer can contaminate an entire load of different polymer. To ensure that there are no contaminants left in the hopper tee, valve or line, the entire assembly must be unbolted and removed. The area is cleaned and then reassembled. This is time consuming and costly.
Since conventional hopper tees are constructed as one piece and must be unbolted to be removed from the line, it would be advantageous to have a hopper tee that can be opened without removal of bolts to allow access to the interior of the tee for complete emptying and cleaning.
Furthermore, some prior art hopper tees do not afford proper ground clearance. Ground clearance has been a problem in the tank industry for years. There are established heights, widths and lengths that tanks must meet by Department of Transportation (DOT) specifications. When the hauler is handling light density products, such as plastic pellets, he needs a larger cubic foot capacity to haul a maximum payload and make hauling such products economically feasible. To increase the cubic foot capacity and still stay within DOT height, width and length standards, the bottom of the hopper needs to be lowered to increase capacity. However, the bottom of the hopper must be designed with angled walls (angle of repose) that funnel down to the hopper tee to allow for emptying. For many dry bulk products the angle of repose needs to be approximately 45xc2x0 to obtain the maximum cubic foot capacity while remaining within the mandated dimensions. Since the hopper tee is mounted below the tank it is obvious that ground clearance problems can arise. For example, when crossing railroad tracks or other uneven surfaces, every inch of ground clearance is important. In the past, tank manufacturers have tried a 30xc2x0 angle of repose. However, such hoppers, because of their lesser incline, do not unload well. Some manufacturers have used a hopper having a 45xc2x0 angle of repose down to the aeration devices and then change the angle to 30xc2x0 which gains a few inches in ground clearance.
In my U.S. Pat. No. 5,842,681, which is incorporated herein by reference, I disclose a swing-away hopper tee which solves may of the above noted problems. The hopper tee disclosed in the above noted patent includes a mounting frame, a butterfly valve and housing assembly, and a tee assembly. The butterfly valve is mounted between the mounting frame and the tee assembly. The tee assembly is pivotally connected to the mounting frame to be able to swing away from the mounting frame. A camming lock assembly is provided to hold the tee assembly in a raised position, and to allow the tee assembly to swing away from the housing.
The mounting frame of the swing-away hopper tee disclosed my last noted patent is fixedly and permanently mounted to the discharge end of the hopper. Although the swing-away hopper tee works extremely well for its intended purposes, it would be desirable to provide a swing-away hopper tee in which the mounting frame can be easily mounted to the discharge end of the hopper and which can be easily dismounted from the discharge end of the hopper for more thorough cleaning or for replacement, when and if necessary.
In accordance with the invention, generally stated, a swing-away hopper tee assembly comprises a mounting frame, tee assembly, and a valve assembly. The hopper tee assembly is removably mountable to a flange at the discharge end of a hopper. To removably mount the hopper tee assembly to the hopper flange, the mounting frame includes a bottom wall, a top wall spaced from the bottom wall, and an outer wall extending between the top and bottom walls to define a channel sized and shaped to receive the hopper flange. The flange includes at least one opening, and a corresponding opening is formed in said channel. A fastener extends through the aligned flange and channel openings to removably secure the mounting frame to the hopper. Preferably, the channel opening is formed in the mounting frame top wall. The mounting frame bottom wall is then sized to expose the flange opening so that the fastener can pass through the flange opening into the channel opening. Additionally, the fastener is an alignment pin which is used to align the position of the valve assembly between the mounting frame and the tee assembly.
The hopper tee assembly is mounted to the flange simply by sliding the mounting frame channel over the hopper flange, aligning the mounting frame hole with the flange hole, and securing said pin in place in said holes.